Cofiring

Co-firing (or cofiring, also referred to as complementary firing or co-combustion) is the combustion of two different fuels in the same combustion system.^[1] Fuels can be solid fuels, liquid fuels or gaseous, and its source either fossil or renewable.^[2] Therefore, use of heavy fuel oil assisting coal power stations may technically be considered co-firing. The term co-firing was popularized in the 1980s and then referred specifically to the use of waste solid residues (paper, plastic, solvents, tars, etc.) or biomass^[3] in coal power stations that were designed only for the combustion of coal.^[4]